From: Oleksandr Andrushchenko Date: Thu, 22 Feb 2018 08:09:19 +0200 Subject: drm/simple_kms_helper: Fix NULL pointer dereference with no active CRTC Git-commit: 4751cf733a1170876dd5ac46f225f5a25f59a67f Patch-mainline: v4.17-rc1 References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166 It is possible that drm_simple_kms_plane_atomic_check called with no CRTC set, e.g. when user-space application sets CRTC_ID/FB_ID to 0 before doing any actual drawing. This leads to NULL pointer dereference because in this case new CRTC state is NULL and must be checked before accessing. Signed-off-by: Oleksandr Andrushchenko Reviewed-by: Daniel Vetter Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/1519279759-7803-1-git-send-email-andr2000@gmail.com Acked-by: Petr Tesarik --- drivers/gpu/drm/drm_simple_kms_helper.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) --- a/drivers/gpu/drm/drm_simple_kms_helper.c +++ b/drivers/gpu/drm/drm_simple_kms_helper.c @@ -112,12 +112,6 @@ static int drm_simple_kms_plane_atomic_c pipe = container_of(plane, struct drm_simple_display_pipe, plane); crtc_state = drm_atomic_get_new_crtc_state(plane_state->state, &pipe->crtc); - if (!crtc_state->enable) - return 0; /* nothing to check when disabling or disabled */ - - if (crtc_state->enable) - drm_mode_get_hv_timing(&crtc_state->mode, - &clip.x2, &clip.y2); ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state, &clip, @@ -128,7 +122,9 @@ static int drm_simple_kms_plane_atomic_c return ret; if (!plane_state->visible) - return -EINVAL; + return 0; + + drm_mode_get_hv_timing(&crtc_state->mode, &clip.x2, &clip.y2); if (!pipe->funcs || !pipe->funcs->check) return 0;